The present invention, in some embodiments thereof, relates to microorganism-comprising particles and, more particularly, but not exclusively, to the use of same for the removal of contaminants from water or soil, for treatment of diseases and for the production of pharmaceutical and cosmetic compositions.
Water quality management is one of the world's most significant concerns. As industry becomes more complex and advanced, problems associated with water pollution become more significant. Consequently, advanced wastewater treatment technology is required. Concentration of industrial waste nutrients such as heavy metals, phosphorous, phenols and oils are difficult to reduce to safe environmental levels. Increasing environmental awareness and the toughening governmental policies, demand new environmentally friendly ways to clean up contaminants using low cost methods and materials. These new technologies for removing nutrients from large volume of wastewater must be economically feasible. For example, physicochemical procedures, such as chemical precipitation, utilizing flocculation-coagulation-sedimentation processes and ion exchange adsorption to exclude heavy metals from wastewater are currently used.
Biological materials and methods, have been extensively studied, and answer some of the above demands, being both economically feasible and capable of coping with large volumes of wastewater.
Biosorption (the ability of certain types of inactive, dead, microbial biomass to bind and concentrate heavy metals from even very diluted aqueous solutions) has proven to be an excellent way to treat industrial waste effluents, offering significant advantages such as low cost, availability, efficiency and ease of operation. Biosorption from aqueous effluents has become a potential alternative to the existing technologies of removal hazard nutrients from industrial wastewater [Shuttleworth, K. L. and R. F. Appl Environ Microbiol (1993). 59(5): 1274-1282].
Bioaccumulation, the gradual accumulation of a certain chemical into living organisms, has been used to clean up contaminated environments such as copper-, zinc- and nickel-contaminated wastewater [Kara Y., Int. J. Environ. Sci. Tech. (2005) 2(1): 63-67].
Biodegradation, the process by which live microorganisms are capable of removing contaminants (e.g. nitrates) from organic material has also been extensively used to clean up contaminated environments (e.g. wastewater). Live microorganisms have the naturally occurring, microbial catabolic diversity to degrade, transform or accumulate a huge range of compounds including hydrocarbons (e.g. oil), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), pharmaceutical substances, radionuclides and metals.
Microorganisms have the ability to remove contaminants (e.g. heavy metals, phosphates and oils) from wastewater by degradation or absorption and the efficiency of such biological processes is high, estimated to give a yield of exclusion of over 99%. As such, a high percentage of ongoing academic research is focused on identifying specialized microorganisms (e.g. bacteria, yeast, fungi and algae) and adapting them to hostile conditions such as wastewater environment. The main challenge is to use living microorganisms in unstable conditions (e.g. pH variations, nutrients inhibition, nutrient enhancement, etc.).
Furthermore, wastewater flora consists of various microorganisms populations co-exiting in a steady state. The efficient use of microorganisms in wastewater treatment requires that the introduced culture be genetically stable and would integrate along with the wastewater natural flora. Introduction of the new culture may be problematic as it may interrupt the flora stability and may lead to undesired effects such as an undesired withdrawal to the former steady state or to elimination of the new microorganisms. Thus, efficiency of the biological process or treatment depends on the threshold concentration (biomass) of the introduced culture. Since the introduced microorganism culture is challenged by natural selection forces (due to environmental adaption), reaching the necessary biomass may be impossible and survival of the introduced culture is extremely difficult.
Biosorption and biodegradation processes using selected bacteria to exclude contaminant nutrients have been commercially previously described. For example, BioPetroClean (BPC) utilizes a bacterial cocktail to remove both dissolved and emulsified hydrocarbons from water, soil, oil storage and transportation tanks. Their technology combines a unique mixture of naturally-occurring bacteria that feed on petroleum hydrocarbons combined with a supplemental nutrient-mix and a controlled oxygen tension and pH which ensures optimal bio-degradation. The BPC technology is based on adaptation of planktonic bacteria blends with the ability to degrade petroleum hydrocarbons.
Furthermore, bioprocessors have frequently been used to grow useful cells or to clean contaminated effluent, such as water. More specifically, biofilms have been widely used because an active biomass produced in the reactor allows large volumetric loadings and good effluent quality without the need for separation of solids. The biofilm bioreactors have been generally categorized as continuously stirred tank reactors (CSTRs), fixed-bed and fluidized bed (described in detail in U.S. Pat. No. 6,235,196).
Numerous publications have described the use of microorganisms to exclude contaminant nutrients such as heavy metals, phosphates and oils from wastewater. Following are some of the cited art.
U.S. Pat. No. 4,530,763 describes methods for treating waste fluids to remove selected chemicals (e.g. minerals and metals) using bacterial cultures. According to their teachings, the bacterial culture is first transferred to a nutrient medium to enable satisfactory bacterial cell growth. The bacterial cells are then attached to a porous fiber webbing supported in a suitable container, the nutrient medium is then replaced with waste fluid for a period of time sufficient to attach the chemical to the bacterial cells. The waste fluid is then removed from the container and the chemical separated from the fiber webbing.
U.S. Pat. No. 6,423,229 describes bioreactor systems for biological nutrient removal. Specifically, U.S. Pat. No. 6,423,229 teaches an integrated biological treatment process and bioreactor system which provides means for simultaneous removal of biodegradable solids, nitrogen and phosphate from water and wastewater. The system comprises microbial consortia immobilized in separate bioreactors for anaerobic processes, phosphate removal and denitrification.